Again,yes! If you have created it, you can copyright it with creative commons, with any type of media: music,videos,pictures,artwork,stories/books,etc!

3.) Can you ‘allow’ others to ‘use’ your copyrighted work and remix it with other content?

Why yes. If you want to, of course. These are called derivatives or changes. The person can change your work, but they might out do your originbal.

4.) Can you share your work online but prevent someone else from being able to make money on what you created (prevent commercial use)?

Yes, of course! You can allow commercial use, which will spread your creation more widely. This also lets you make money from it! Or, you can prohibit commercial use, so no one can make money off your creation but you.